The present invention relates generally to a grease lock seal for use with a universal joint on a vehicle drive shaft.
Typically, in a universal joint bearing, the sealing lips of a grease seal are angled away from the internal bearing components. When the system is re-greased, the internal pressure increases and the sealing lips flex open and lose contact with the sealing surface, allowing grease to purge from the system.
Grease is also purged from the system as centrifugal forces are introduced as the drive shaft spins. The pressure increases as the system rotates, and the sealing lips flex open and lose contact with the sealing surface and allow grease to escape from the system.
Also, at times the ability to replace the internal grease is desirable due to customer demand or because the vehicle operates under off road conditions which accumulates unwanted dirt and debris in the grease. It is therefore desirable to have a purge mechanism in the grease seal to allow old grease to escape.
Hence, there is a need in the art for a grease lock seal for use with a vehicle drive shaft which retains grease in the system.
An inventive embodiment includes a grease lock seal for use with a universal joint on a vehicle drive shaft.
In a preferred embodiment, a grease lock seal is press fit on a vehicle universal joint cross-member and includes a seal portion and a metal housing. The seal portion includes a plurality of sealing lips angled inwardly towards the internal bearing components and a shoulder seal which prevents contaminants from contacting the plurality of sealing lips. The seal portion substantially contacts the outer bearing surface of a trunnion and the metal housing substantially contacts the inner bearing surface of a bearing cup. Because the sealing lips are angled upwardly towards the bearing components, grease does not purge from the system as the internal pressure increases due to the addition or grease or due to centrifugal forces which are introduced during the rotational operation of the system. Therefore, the system does not have to be re-greased.
An alternative embodiment of the invention allows for the option of re-greasing. A plurality of grease purge channels are formed into the metal housing and form a path for grease to be purged from the system. As the internal pressure increases during regreasing, the used grease flows through the grease purge channels and out of the system. The grease purge channels are small enough so that grease does not escape from the system during normal operations.
Accordingly, the present invention provides a grease lock seal for use with a universal joint of a vehicle drive shaft.
These and other features of the present invention will be best understood from the following specification and drawings.